Headlight dimmer system



Sept. 30, 1958 c. -w. MILLER ETAL. 2,

' HEADLIGHT DIMMER SYSTEM Filed Feb. 3, 1956 &|.

' Z/GHT CONTMlED CZQCU/T Inventors afar/er flfiilim QZ/ Z v aw lwpmzfi Attorney nited States Patent (llfiice 2,854,604 Patented Sept. 30, 1958 HEADLIGHT DIMMER SYSTEM Charles W. Miller and George W. Onksen, Anderson, and Myrneth L. Woodward, Lapel, 1nd,, assignors to General Motors Corporation, Detroit, Micln, a corporation of Delaware Application February 3, 1956, Serial No. 563,373 Claims. (Cl. 315-83) This invention relates to automatic switching means and more particularly to automatic timed switching control means adapted to be connected to light controlled multifilament lamp circuits to introduce a distinguishing or characteristic flash of the lamps.

Many highway vehicles having the conventional high and low beam filament headlamps are currently also supplied with automatic light sensitive control means to switch from high beam to low beam illumination upon the approach of a vehicle from the opposite direction. This action is ordinarily accomplished manually by the driver. It would be advantageous to advise the approaching driver as to when the vehicle was equipped with automatic light control means for switching from high to low beam.

It is therefore an object in making this invention to provide means for advising the approaching driver when the headlamps are under manual or whether they are under automatic control.

It is a further object in making this invention to provide means for introducing a characteristic or distinguishing flash in an automatic headlamp dimming system to advise the approaching driver that the car is equipped with automatic dimming apparatus.

It is a still further object in making this invention to provide means for reenergizing the high beam filaments once in proceeding from high to low beam energization as controlled principally by light sensitive control means.

With these and other objects in view which will become apparent as the specification proceeds, our invention will be best understood by reference to the following specification and claims and the illustrations in the accompanying drawings, in which:

Figure 1 is a circuit diagram of a control system for multifilament lights embodying our invention; and

Figure 2 is a circuit diagram of a control system embodying a modified form of our invention.

Referring now more particularly to Figure 1, there is shown therein as illustrative of a pair of headlamps, one lamp 2 having bright or long range filaments 4 and dim or short range filaments 6. The bright filaments 4 are connected to stationary contact 8 of relay 10 shown in dash line outline. A second spaced stationary contact 12 of the relay 10 is connected to the dim filaments 6. Pivotally mounted to alternately engage the two stationary contacts 8 and 12 is an armature 14 that is spring biased by spring 16 into engagement with contact 8 but which is pulled away from contact 8 and into engagement with contact 12 by energization of relay coil 18.

A source of electrical power such as the vehicle storage battery is connected to power line 20 which is directly connected to one terminal of the relay coil 18 and also to armature 14. A regulating resistor 22 is connected directly across the relay coil 18 to regulate the voltage. A second compound control relay 24 is provided to control the first relay to flash the bright filaments once in passing from bright to dim beam illumination. This relay includes a central core 26 around which the relay coil 28 is wound and two armatures 30 and 32 which are pivotally mounted on the core near one end. Armature 32 is attracted toward the core when the coil is energized. The armature 30, however, is nonmagnetic and is biased toward the core but held away from the core by a hot wire element which stretches when it is heated. This hot wire, indicated at 34, has one end anchored to the housing and the opposite end electrically insulated from but mechanically connected to the upper end of the armature 36, as shown in Figure 1, to restrain that end from moving inwardly toward the core. The insulating bead 36 connects the upper end of the wire 34 with the armature 30, but at the same time electrically insulates it therefrom. When the wire 34 is cold the upper end of the armature 30 is kept in an outward position, as shown, but as the wire heats up it stretches and the armature 36 may move toward the core to actuate certain switches.

The upper end of the hot wire 34 is electrically connected through line 38 and ballast resistance 40 to the power supply line 26. The armature 30 is conductively connected to the core 26, the latter being electrically connected through line 42 with a stationary contact 44 on switch 46, the movable arm 48 of which is grounded. The position of the movable arm 48 is controlled by the light controlled circuit 50 shown herein by a block diagram. Switch 46 is normally open when no light falls on the light control circuit, but closes when a sutficient amount of light impinges on the same. Armature 30 engages a back contact 52 when in its outward position. Contact 52 is connected through ballast resistor 54 with the upper terminal of relay coil 18. Armature 30 also engages contact 56 when it is permitted to move inwardly .by the expansion of the hot wire 34. Contact 56 is connected to one end of the relay coil 28, and it is also electrically connected to a second contact 58 which cooperates with the second relay armature 32. The remaining terminal of the relay winding 28 is connected through line 68 to the upper end of relay coil 18. Armature 32, likewise electrically connected to the core 26, engages stationary contact 58 when in its inward or attracted position and a further spaced stationary contact 62 when in its outer :or released position. Contact 62 is electrically connected through line 64 with the lower terminal of the hot wire 34.

The operation of this control system is as follows. Assuming that the system is connected to a suitable source of power such as the vehicle battery, and that the car is being operated in an area in which no approaching vehicles are present, switch 46 will be open and the bright filaments of the headlamps will be energized through the following circuit: from the source of power, through line 20, to armature 14, contact 8, bright filaments 4, to ground. At this time the circuit through relay coil 18 is incomplete due to switch 46 being open. Assuming now that a vehicle approaches to direct sufiicient light on the photo-controlled switch 50 to close switch 46, this will complete the energizing circuit for the coil 18 through the following circuit: source of power, line 20, coil 18, resistor 54, contact 52, armature 30, core 26, line 42, contact 44, armature 48, to ground. The energization of coil 18 causes it to attract its armature 14 to move it from engagement with stationary contact 8 into engagement with contact 12. This thus deenergizes the bright filaments and energizes the dim filaments through an obvious circuit.

At the same time a circuit is completed through the.

ballast resistance 4d, line 38, hot wire 34, line 6 back contact 62, armature 32, core 26, line 42., contact 44, armature 48, to ground. The resistance in the hot wire then causes it to heat up due to the How of current therethrough and the hot wire 34 stretches, and armature 3t begins to move toward the core as, due to a mechanical bias in that direction. What it has moved a short distance the armature 3d breaks contact with stationary contact 52, thus deenergizing relay coil 18, and armature M then moves back to its upper position to reenergize the bright filaments As the hot wire 34 continues to heat and expand, armature 3@ reaches a point where it contacts stationary contact 56. When this point is reached, a second energizing circuit for relay coil 13 is established, which may be traced as follows: from the upper end of relay coil it through line 60, relay coil 28, contact 56, armature 30, core 26, line 42, contact 44, armature 48, to ground. This second energization will again pull armature l4 downwardly to break the circuit to the bright filaments and complete one for the dim filaments. Thus a single flash of high filaments is provided once in proceeding from high to low beam illumination.

Upon reaching the limit of inward movement of armature 3% to engage contact the coil 28 is included in circuit with the relay coil 18. Thus coil 28 attracts armature 32, to move from the outer or position shown to an inner or attracted position. When armature 32 has moved inwardly, the contact with stationary contact 58 completes a holding circuit for both the relay coil 23 and relay coil This circuit is from the upper end of relay coil 18 through line 66, relay coil 23, contact $6, contact 53, armature 32, core 26, line 42, contact 44, armature 48, to ground. Thus these two coils will remain energized from this point on until switch do is opened by the removal of light on the light controlled circuit 5%. In the meantime, however, the circuit through the hot wire 34 has been broken by movement of armature 32 away from stationary contact 62, and as this wire begins to cool it moves armature 3t back toward the outer or left-hand position. This movement continues until the armature engages stationary contact 52 where it remains in readiness for the next energizing cycle. By the use of this circuit, therefore, a single advisory flash of high beam filaments is produced in changing from high to low beam illumination.

Referring now to the modified form of control circuit shown in Figure 2, there is shown therein a similar control relay it? having an operating winding 18 for switching armature 14 between an upper stationary contact 8 and a lower stationary contact 12 for alternately energizing dim filaments 6 and bright filaments l. The 12- volt source is shown connected directly through line with One end of the relay coil is, and it is also connected through a ballast resistor 53 and line iii to one end of a relay operating coil 72 of a compound timing relay "id. The remote end of operating coil '72 is connected to two spaced stationary contacts 76 and 78. The relay 74 has two pivotally movable armatures. The first, 870 is formed of magnetizable material and is attracted upwardly as shown in Figure 2 by the field of the operating coil 72. The second, 82, is nonmagnetic, pivots around its left-hand end as shown in Figure 2, and may move downwardly by the expansion of a hot wire 86 which supports the right-hand end. The hot wire 84 is insulatedly mounted to the base through an insulating head so, and is directly connected at its opposite end to the armature 3.4. Hot wire 8 is connected through line 8? to contact 93 mounted on the outer movable end of armature 39, but electrically insulated therefrom. This movable contact 9d engages a stationary contact 92 connected to line 7t when the armature is in its lowermost or released position. Armature also carries a cooperating contact M which engages stationary contact '73.

The movable end of the nonmagnetic armature d2 carries two contacts as and 93, the first of which is adapted to engage a stationary contact connected through line 16?. with the upper end of the relay coil 18, and the second, 93, which is adapted to engage stationary contact 76 when the armature 82 is in its lowermost position. Both armatures 82 and 80 are connected conductively together and through line 104 to stationary contact 1%. A movable armature 103 whose position is determined by energization of an operating coil adapted to engage stationary contact 106. Armature 168 is spring biased toward contact 106, but can be moved away from that contact by the light controlled circuit 112 connected to the coil 116 which actuates the armature.

The operation of this circuit is as follows. When the car is being operated on suburban or country roads with no cars approaching, the high beams 4 are illuminated by an obvious circuit, and the relay coil is energized to hold the armature MP8 to the left. If an automobile approaches from the oposi'te direction and light from its headlights impinges on the light control means 112, relay coil 1141 is deenergized and armature 108 moves over into engagement with stationary contact 106. This completes a circuit through "the relay coil lit-S and causes a switching from high to low beams. The energizing circuit is as follows: from the source of power, through line 66, relay coil 18, line 1 02, contact till), contact 96, armature 32, line M4, contact 106, armature 108, to ground. This causes the lights to switch to low beam. At the same time a second circuit is completed through the hot wire 34. This circuit is from the source of power through ballast resistor 68, contact 92, contact 9:), line 33, hot wire 84, armature 82, line 104, contact 106, armature 1%, to ground. Thus current is applied to the hot wire and it begins to lengthen, permitting armature 32 to move downwardly about its left-hand end pivot.

The list movement of the armature 82 will cause contact as to move away from contact 100, opening the energizing circuit for relay coil 13, which causes the headlamps to switch back to high beam illumination by movement of the armature i4. Further movement of the armature 8 2: causes contact 98 to engage contact 76 which completes an energizing circuit for the relay coil '72 and it therefore attracts armature 38, opening the circuit through the hot wire 84, and at the same time closing a holding circuit for coil '72 through contacts 78-)4. Opening of contacts 992 opens the circuit to the hot wire 34, and closing of contacts 73-54 completes the holding circuit for the coil 72. At this point relay coil is is still deenergized but hot wire 84- is now no longer being heated so it begins to contract, moving armature 32 back up to its original position as shown. When it reaches that position it recompletes the energizing circuit for the coil llfi and the relay it switches back to low beam illumination, where the system will remain until the light controlled circuit 112 again becomes energized through a removal of the impinging light and breaks the circuit between contact 166 and armature 108. This circuit also provides a flash of the high beam filaments in proceeding through automatic control from high to low beam illumination due to the approach of other vehicle headlights.

We claim:

1. In a control system, electric illuminating means having a plurality of filaments for providing different illumination conditions, a source of electrical power, switching means connected to the source of power and the filaments to alternately energize the same, coil means for operating said switching means, a second switching means connected to the coil means and to the source of power to control the first-named switching means, expansible means connected to said second switching means whose length varies with temperature and which controls the position of the same, a third switching means electrically connected to the expansible means and to the source of electrical power to heat the expansible means by current flow thcrethrough, and second coil means connected to the source of power and the first coil to actuate the third switching means.

2. In a control system, a multiple filament lamp, a source of electrical power, switching means connected to said filaments and to the source for alternately energizing the filaments, light controlled switching means connected in series with said first-named switching means to control the actuation of the latter, hot wire actuated switching means connected in said series circuit with the firstnamed switching means and light controlled switching means and energized once when the first-named switching means is actuated to provide a single cyclic operation upon operation of the first-named switching means, and means for connecting the hot wire actuated means to the source of power.

3. In a control system, a source of electrical power, electric lamp means, a light controlled switch, relay switching means connected to the lamp means and in series relation with the source of power and the light controlled switch to control the lamp means in response to the light controlled switch position, a heat actuated control switch also in series with the relay switching means to cyclically control the relay switching means, heat sensitive actuating means for the heat actuated control switch, a second relay control switching means connected to the heat sensitive actuating means and to the source of power to control energization thereof and a holding circuit connected to said second relay to limit energization of said heat sensitive means to once per cycle of the first relay switching means.

4. In a control system, lighting means for automotive vehicles having short and long range filaments for illuminating the highway ahead of the vehicle, a source of electrical power, a first switching means connected to the ,source of electrical power and to the short and long range filaments to alternately energize the same, a first relay means for actuating said first switching means, a second switching means, a light controlled switching means, said second switching means and said light controlled switching means being connected in circuit with the first relay means and source of electrical power, said second switching means being normally clcsed, heat responsive actuating means for said second switching means and a further relay switching means connected to toe first relay means and the heat responsive actuating means to control the latter and a holding circuit for the latter so that only one cycling or flash of filaments will result from an actuation of the first switching means.

5. In a control system for long and short range electric lamps on automotive vehicles having a light sensitive system for switching from one range to another dependent upon the amount of incident light on the vehicle, means to provide a single flash of the long range lamps in switch- F ing from long range to short range lamps under control of a light sensitive switch, said means comprising a main control relay and a source of electrical power connected in circuit with the electric lamps to alternately energize one range or the other, a compound heat responsive and coil actuated switching means connected to the source of electrical power and to the main control relay including a plurality of movable arms and associated contacts, one arm being actuated by the heat responsive means and having normally closed contacts in circuit with the main control relay and a second arm actuated by said coil and having contacts in circuit with the heat responsive means and to the coil to control the generation of heat and a holding circuit for the coil so that only a single heat generator cycle is provided each time the lamps are switched from long to short range.

References Cited in the file of this patent UNITED STATES PATENTS 1,774,101 Lorimer Aug. 26, 1930 2,388,033 Berninger Oct. 30, 1945 2,681,394 Hollins June 15, 1954 FOREIGN PATENTS 916,039 France Aug. 5, 1946 

